Vertebrates and Invertebrates: Introduction to Vertebrates and Invertebrates (For CBSE, ICSE, IAS, NET, NRA 2023)

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Introduction to Vertebrates

  • Vertebrates are those animals, which comprise all species of animals within the subphylum Vertebrata.
  • They represent much of the phylum chordata.
  • They include groups such as:
    • Jawless fishes
    • Bony fishes
    • Tetrapod՚s, which include amphibians, reptiles, birds, and mammals
    • Jawed vertebrates, which include the cartilaginous fishes (sharks, rays, and ratfish)
Introduction of Vertebrates

Characteristics of Vertebrates

  • All basal vertebrates breathe with gills.
  • The central nervous system of vertebrates is based on a hollow nerve cord running along the length of the animal.
  • The defining characteristic of a vertebrate is the vertebral column.
  • There is a notochord, which is present as an embryo in all humans and all other vertebrates.
  • The mouth is present at the anterior portion.
  • The alimentary canal ends in the anus.

Classification of Vertebrates

Classification of Vertebrates


  • These animals neither possess nor develop a vertebral column (commonly known as a backbone or spine) .
  • Apart from subphylum Vertebrate, it includes all animals.
  • Invertebrates are so many with different sizes and shapes.
  • These animals do not have a backbone.
  • Some of the examples of invertebrates include:
    • Arthropods (insects, arachnids, crustaceans, and myriapods)
    • Mollusks (chitons, snail, bivalves, squids, and octopuses)
    • Annelid (earthworms and leeches)
Animal: Invertebrates

Characteristics of Invertebrates

  • Invertebrate՚s do not possess lungs and they respire through their skin.
  • They are heterotrophic since they cannot produce their own food.
  • In all the invertebrates, there may not be a spinal cord or vertebral column.

Kinds of Invertebrates

Ancestral Mollusc

Ancestral Mollusc

Anatomical Diagram

Phylum Annelida

Phylum Annelida


Q 1. What are the groups included in Vertebrates?


Some of the groups included in vertebrates are:

i) Jawless fishes

ii) Bony fishes

iii) Tetrapod՚s, which include amphibians, reptiles, birds, and mammals

iv) Jawed vertebrates, which include the cartilaginous fishes (sharks, rays, and ratfish)

Q 2. What is the classification of Vertebrates?


There are seven classifications of Vertebrates:

i) Birds

ii) Mammals

iii) Reptiles

iv) Amphibians

v) Cartilaginous fishes